MOGADISHU, March 28 (Xinhua) -- Two explosions rocked the northeastern Somali region of Puntland overnight, killing at least one person and wounding three others, all Ethiopian nationals, reports and officials said on Saturday.

Abdulahi Saeed Samatar, local minister for security, told Xinhua that the blast in Garowe, the regional capital, was caused by a hand grenade and confirmed the death of one person and injury of three all from neighboring Ethiopia but denied the occurrence of an explosion in Bossaso.

But media reports and residents in the port city of Bossaso said that huge explosion was heard late in the night near the headquarters for the local security service, the Puntland Intelligence Service (PIS) in an exclusive area in the commercial city of Bossaso. It was not immediately clear if there was any casualties.

The area around the PIS headqaurters was reportedly cordoned off and officials remained tightlipped about the situation in the area.

On Monday, PIS agents detained a well known local cleric, shiekh Osman, triggering riots by residents angry at the arrest of the respected scholar.

The local government did not say why the cleric was arrested but local media reports quoting unnamed government sources said the cleric was suspected of having links with the hard-line Islamist group of Al-shabaab which controls much of south and central Somalia.

Last year another huge explosion targeted the headquarters of PIS. The blast killed one person and wounded several others. The explosion in Bossaso, blamed on Al-shabaab, was part of coordinated suicide attacks on both Puntland and Somaliland in the far northwest where nearly 30 people were killed.

The two regions are relatively stable compared to the restive war-stricken south and central part of Somalia.